Also you could look at how we did it with codecast, it's open source on GitHub search for codecast France ioi
With mouse relative position, highlights selections of code etc
We also created a while back codecast for my courses in c programming. I also have Linux running entirely in the browser.
And the c programming language "running" fully in the browser. Everything in sync with your oral explanations.
I have also used it for a year or so and restored some files individually without any problem. I use a remote ssh storage through tailscale, just very stable interestingly! Only small problem was that my server broke during an uptade because I created a systemd service to start it and the parameters changes to start it. Apart from that, very stable for now.
Haha I saw a few hours ago immich on top of HN, wanted to tell everybody I'm using photoprism + syncthing for quite a long time now and I see that photoprism made it to the top , well, good !